Write a short note on Quasi-static process .

Explanation

Quasi - static process : A Quasi - static process can be defined as an infinitesimally show process in which at each and every intermediate stage the system remains in thermal and mechanical (themodyamic ) equilibrium with the surroundings through out the entire process .

Explanation : A non-equilibrium thermodynamic system can be treated as an idealized process in which at every stage the system is in equilibrium astate .
In a thermodynamic system let the piston moves in a frictionless manner . Instead of sudden compression of piston imagine the piston moves very very slowly i.e., it appears almost static . Then the pressure inside the cylinder `P+DeltaP` and temperature `T+DeltaT` are almost equal to external pressure P and temperature T .
Since for extremely slow process the values of `DeltaP and DeltaT` are so small that we can treat `P+DeltaP andT+DeltaT=T` . Such type of process is called Quasi static process .
For Example , to take a gas from the state (P.T) to another state (P.T) , via a quasistatic process , we change the external pressure / temperature by a very small amount and allow the system to equalise its pressure /temperature with the surroundings .
Continue the process infinitely slowly till the final state (P.T) is attained
A quasi- static process is a hypothetical construct . The process must be infinitely slow, should not involve large temperature differences or accelerated motion of the piston of the container .